The invention generally relates to the field of packaging machines for producing packages from a packaging material web, more particularly to a feeding chain for use in packaging machines of this kind and comprising improved clamping members for clamping the lateral edges of the packaging material web.
Conventional web feeding chains are formed with first clamping members secured on the chain links and second cooperating clamping members at one end of a guiding shaft guided in a guiding opening of a first clamping member. The guiding shaft is surrounded by a flanged sleeve which has its flange portion adjacent the first clamping member. A pressure spring engages between the flange portion of the sleeve and the bent ends of laterally guided tags which are provided on the clamping member.
The packaging machines equipped with feeding chains of this kind have two spaced sprocket wheels on which the feeding chain is passed. A disc member is associated with one of the sprocket wheels to operate the clamping members at the position where the web should be engaged by the clamping members. To this end, the disc member has a conical lateral face inclined with respect to the rotational axis of the disc. The clamping jaws are opened when they engage the inclined conical face. The clamping jaws are guided by twin lugs and a bottom plane formed thereby and cooperating with the conical engagement surface. This arrangement, however, allows no positive guiding in circumferential direction or perpendicularly to this direction.